The retina is a specialized neural structure that transforms an image into electrical signals which are then transmitted to the rest of the brain. A fundamental strategy used by the mammalian retina to cope with a wide range of incident light intensities and wavelengths is to segregate inputs into different processing pathways. For example, rod and cone signals are processed by separate bipolar cells, as are signals arising in blue- and longer wavelength-sensitive cones. Recent anatomical and physiological results, however, have challenged this view of segregated circuits at the level of the cone to bipolar cell contacts. Specific Aim 1 will use confocal microscopy to comprehensively map the contacts between the different types of photoreceptors and identified bipolar cells; Aim 2 will determine the function of unorthodox synaptic connections using cell-pair recording in retinal slices; and, Aim 3 will determine the consequences of signal mixing for the normal function of the retina. A multiplicity of bipolar cell pathways carrying signals from the outer to the inner retina may provide the retina with some redundancy when specific pathways are damaged by disease. [unreadable] [unreadable]